Immunolocalization of Alla to tro pin Neuro pe ptide in the Developing Brain of the Silk MothBombyx mori

Abstract

Polyclonal antiserum against Manduca sexta allatotropin has been utilized to investigate the localization of allatotropin‐immuno reactivity in the brain of the silk moth Bombyx mori. Manduca sexta allatotropin‐immuno reactive (Mas‐AT‐IR) neurons were found in all larval brains investigated, but not in prepupal, pupal and adult brains. In the larval stages, first appearance of Mas‐AT‐immuno re activity was shown in the brain of first instar larvae, which contains four pairs of bilateral Mas‐AT‐IR cell bodies. Labeled neurons increased to six pairs in the second instar larval brain, including two pairs of median neurosecretory cells in the pars intercerebralis. In the third and fourth instar larvae, five pairs of labeled cell bodies were distributed throughout each brain. In the fifth instar, there were about ten pairs of bilateral cell bodies in the day‐1 brain, about seven pairs in the day‐3 brains, and five pairs in the day‐5 brains, respectively. Mas‐AT‐labeling was observed in both axons within nervi corpora cardiaci (NCQ B‐n and corpora allata. This suggests that the Mas‐AT produced from the brain neurons is transported via some axons of the NCC I+II and nervi corpora allati I to the corpora allata, which appears to be a main accumulation site for the Mas‐AT neuropeptide in some brain neurons produced in B. mori.